Hydraulic Cylinder Force Calculator (Push and Pull)
Extending and retracting force of a double acting hydraulic cylinder, from bore diameter, rod diameter and working pressure entered in bar, MPa or psi. Push force uses the full piston area while pull force uses the annulus area, which is why a cylinder always retracts with less force than it extends.
How to use this calculator
- Enter the bore diameter and the piston rod diameter. Leave the rod at 0 for a plunger or ram cylinder.
- Enter the working pressure and select its unit: bar, MPa or psi.
- Set the mechanical efficiency if you want seal and leakage losses included, otherwise leave it at 100 percent for the theoretical force.
- Read the extending and retracting force, the piston and annulus areas, and the ratio between them.
Frequently asked questions
How do I calculate hydraulic cylinder force?
Force is pressure times effective area. For the extend stroke F = p x pi/4 x D^2 with D the bore diameter. For the retract stroke F = p x pi/4 x (D^2 - d^2) with d the rod diameter, because the rod occupies part of the piston face that the oil can act on.
Why is the retracting force lower than the extending force?
On the retract stroke only the annulus area is pressurised, that is the piston area minus the rod cross section. A 63 mm bore with a 36 mm rod gives 3117 mm2 against 2099 mm2, so it pulls about two thirds of the force it pushes.
What pressure do hydraulic cylinders normally run at?
Mobile hydraulics usually run at 200 to 350 bar and industrial systems at 70 to 210 bar. The cylinder's own rated pressure sets the limit, so never exceed the rating on the nameplate.